《Python語言程序設(shè)計》課件-第四章（中英文課件）

Python語言程序設(shè)計【列表基礎(chǔ)】PythonLanguageProgramming[ListBasics]知識點【訪問列表中的值】1234aList=['Deris','Weng',1,2]

bList=[1,2,3,4,5,6,7]

print("aList[0]:",aList[0])

print("bList[1:5]:",bList[1:5])【例】使用下標(biāo)索引來訪問列表aList[0]:DerisbList[1:5]:[2,3,4,5]輸出結(jié)果：KnowledgePoints[Accessingvaluesinthelist]1234aList=['Deris','Weng',1,2]

bList=[1,2,3,4,5,6,7]

print("aList[0]:",aList[0])

print("bList[1:5]:",bList[1:5])[Example]UsingasubscriptindextoaccessalistaList[0]:DerisbList[1:5]:[2,3,4,5]Outputresult：知識點【列表的更新】1234aList=['Deris','Weng',1,2]

print("第三個元素為:",aList[2])

aList[2]=3

print("更新后的第三個元素為:",aList[2])【例】列表的更新第三個元素為:1更新后的第三個元素為:3輸出結(jié)果：[Updatestothelist]1234aList=['Deris','Weng',1,2]

Print("Thethirdelementis:",aList[2])

aList[2]=3

Print("Thethirdupdatedelementis:",aList[2])[Example]UpdatestothelistThethirdelementis:1Theupdatedthirdelementis:3KnowledgePointsOutputresult：知識點【向列表指定位置插入元素】123aList=['Deris','Weng',1,2]

aList.insert(2,'Happy')#使用insert向索引2的位置插入元素‘黃金分割’

print("aList結(jié)果為:",aList)#列表中有5個元素【例】向列表插入元素aList結(jié)果為:['Deris','Weng','Happy',1,2]輸出結(jié)果：[Insertanelementintothelistatthespecifiedposition]123aList=['Deris','Weng',1,2]

AList.insert(2,'Happy')#Useinserttoinserttheelement'GoldenSection'intothepositionofindex2

Print("aListresultsare:",aList)#Thereare5elementsinthelist[Example]InsertingelementsintoalistTheaListresultis:['Deris','Weng','Happy',1,2]KnowledgePointsOutputresult：知識點【刪除或清空列表中的記錄】1234aList=['Deris','Weng',1,2]

print("刪除前的列表:",aList)

delaList[2]

print("刪除第三個元素后的列表:",aList)【例】利用del語句刪除列表中的元素刪除前的列表:['Deris','Weng',1,2]刪除第三個元素后的列表:['Deris','Weng',2]輸出結(jié)果：[Deleteoremptyrecordsinthelist]1234aList=['Deris','Weng',1,2]

Print("Listbeforedeletion:",aList)

delaList[2]

Print("Listafterdeletingthethirdelement:",aList)[Example]DeleteelementsinthelistwithdelstatementListbeforedeletion:['Deris','Weng',1,2]Listafterdeletingthethirdelement:['Deris','Weng',2]KnowledgePointsOutputresult：知識點【刪除或清空列表中的記錄】123456aList=['Deris','Weng',1,2]

#列表本身不包含數(shù)據(jù)，而是包含變量：aList[0]到aList[3]

first=aList[0]#拷貝列表，創(chuàng)建新的變量引用，而不是數(shù)據(jù)對象的復(fù)制。

delaList[0]#del刪除的是變量，而不是數(shù)據(jù)。

print(aList)

print(first)【例】del語句作用在變量上，而不是數(shù)據(jù)對象上['Weng',1,2]Deris輸出結(jié)果：pop方法刪除列表中的元素123456aList=['Deris','Weng',1,2]

#Thelistitselfdoesnotcontaindata,butcontainsvariables:aList[0]toaList[3]

first=aList[0]#Copythelistandcreateanewvariablereferenceinsteadofcopyingdataobjects.

delaList[0]#deldeletesvariables,notdata.

print(aList)

print(first)[Example]delstatementsactonvariables,notdataobjects['Weng',1,2]DerisThepopmethoddeletestheelementsinthelist[Deleteoremptyrecordsinthelist]KnowledgePointsOutputresult：知識點【遍歷列表、二級索引】123aList=['Deris','Weng',1,2]

foriinaList:

print(i)【例】列表的遍歷DerisWeng12輸出結(jié)果：[Traversinglists,secondaryindexes]123aList=['Deris','Weng',1,2]

foriinaList:

print(i)[Example]IterationofalistDerisWeng12KnowledgePointsOutputresult：知識點【遍歷列表、二級索引】12aList=['Deris','Weng',[1,2,3]]

print(aList[2][0])【例】列表的二級索引1輸出結(jié)果：12aList=['Deris','Weng',[1,2,3]]

print(aList[2][0])[Example]Secondaryindexofalist1[Traversinglists,secondaryindexes]KnowledgePointsOutputresult：Python語言程序設(shè)計【索引的使用+元素數(shù)量+列表運算符】PythonLanguageProgramming[Useofindexes+numberofelements+listoperators]索引俗稱下標(biāo)。索引值從0開始，直到長度減1位置（例如對10個元素的列表，最大的索引值為［9］）。

知識點【索引的使用】12aList=[1,2,3,4,5,6,7]

print("aList[3]:",aList[3])【例】使用下標(biāo)索引來訪問列表aList[3]:4輸出結(jié)果：IndexCommonlyknownassubscripts.Theindexvaluestartsfrom0andgoestothelengthminus1position(e.g.foralistof10elements,themaximumindexvalueis[9]).Forexample,foralistof10elements,themaximumindexvalueis[9])KnowledgePoints[UseofIndexes]12aList=[1,2,3,4,5,6,7]

print("aList[3]:",aList[3])[Example]UsingasubscriptindextoaccessalistaList[3]:4Outputresult：知識點【索引的使用】123x=[1,2,3,4,5,6]

print(x[6])#最大的索引值

print(x[-7])#最小的索引值【例】索引越界Traceback(mostrecentcalllast):File"indexError.py",line3,in<module>print(x[6])IndexError:listindexoutofrange輸出結(jié)果：123x=[1,2,3,4,5,6]

print(x[6])#Maximumindexvalue

print(x[-7])#Minimumindexvalue[Example]IndexoutofboundsTraceback(mostrecentcalllast):File"indexError.py",line3,in<module>print(x[6])IndexError:listindexoutofrangeKnowledgePoints[UseofIndexes]Outputresult：函數(shù)len()求集合中的元素數(shù)量知識點【求元素數(shù)量】1234x=[1,2,3,4,5,6]

y=[]

print(len(x))

print(len(y))【例】函數(shù)len()60輸出結(jié)果：Functionlen()tofindthenumberofelementsintheset[Numberofelementstobefound]1234x=[1,2,3,4,5,6]

y=[]

print(len(x))

print(len(y))[Example]Functionlen()60KnowledgePointsOutputresult：

+

和

*

的操作符+號用于組合列表，*號用于重復(fù)列表知識點【列表運算符】12345print([1,2,3,4]+[5,6])#列表的拼接

print(5in[1,2,3,4,5,6])#元素是否存在于列表中

print(['Weng']*3)#列表的重復(fù)倍增

forxin[1,2,3]:#列表的迭代

print(x,end="")【例】列表運算符[1,2,3,4,5,6]True['Weng','Weng','Weng']123輸出結(jié)果：

+and*operatorsThe+signisusedforcombininglists,the*signisusedforrepeatinglists[Listoperators]12345print([1,2,3,4]+[5,6])#Splicingoflists

print(5in[1,2,3,4,5,6])#Whethertheelementexistsinthelist

print(['Weng']*3)#Duplicatemultiplicationofthelist

forxin[1,2,3]:#Iterationoflist

print(x,end="")[Example]Thelistoperator[1,2,3,4,5,6]True['Weng','Weng','Weng']123Outputresult：KnowledgePointsPython語言程序設(shè)計【列表函數(shù)&方法】PythonLanguageProgrammingListFunctions&Methods知識點【列表函數(shù)】1.列表函數(shù)函數(shù)描述len(list)計算列表元素個數(shù)max(list)返回列表元素最大值min(list)返回列表元素最小值list(seq)將元組轉(zhuǎn)換為列表12345a=['Hello','Deris','Weng']

n=[1,2,3]

print(len(a))

print(max(a))

print(min(n))【例】列表函數(shù)的使用3Weng1輸出結(jié)果：KnowledgePoints[ListFunctions]1.thelistfunctionfunctionDescriptionlen(list)countsthenumberofelementsinthelistmax(list)Returnsthemaximumvalueofthelistelementmin(list)Returnstheminimumvalueofthelistelementlist(seq)Convertingtuplestolists12345a=['Hello','Deris','Weng']

n=[1,2,3]

print(len(a))

print(max(a))

print(min(n))[Example]Theuseofthelistfunction3Weng1Outputresult：知識點【列表函數(shù)】1234a=['Hello','Deris','Weng']

n=[1,2,3]

x=[a,n]

print(min(x))【例】列表函數(shù)的錯誤使用Traceback(mostrecentcalllast):File"ListError.py",line4,in<module>print(min(x))TypeError:'<'notsupportedbetweeninstancesof'int'and'str'輸出結(jié)果：1234a=['Hello','Deris','Weng']

n=[1,2,3]

x=[a,n]

print(min(x))[Example]MisuseofthelistfunctionTraceback(mostrecentcalllast):File"ListError.py",line4,in<module>print(min(x))TypeError:'<'notsupportedbetweeninstancesof'int'and'str'KnowledgePoints[ListFunctions]Outputresult：知識點【列表方法】2.列表方法方法描述list.append(obj)在列表末尾添加新的對象list.count(obj)統(tǒng)計某個元素在列表中出現(xiàn)的次數(shù)list.extend(seq)在列表末尾一次性追加另一個序列中的多個值（用新列表擴(kuò)展原來的列表）list.index(obj)從列表中找出某個值第一個匹配項的索引位置list.insert(index,obj)將對象插入列表list.pop(obj=list[-1])移除列表中的一個元素（默認(rèn)最后一個元素），并且返回該元素的值list.remove(obj)移除列表中某個值的第一個匹配項list.reverse()反向列表中元素[Listmethod]2.ThetabularapproachMethodsDescriptionlist.append(obj)Addsanewobjecttotheendofthelistlist.count(obj)countsthenumberoftimesanelementappearsinthelistlist.extend(seq)Appendmultiplevaluesfromanothersequenceatoncetotheendofthelist(extendstheoriginallistwithanewlist)list.index(obj)Findstheindexpositionofthefirstmatchofavaluefromthelistlist.insert(index,obj)Inserttheobjectintothelistlist.pop(obj=list[-1])Removesanelementfromthelist(defaultstothelastelement)andreturnsthevalueofthatelementlist.remove(obj)removesthefirstmatchofavalueinthelistlist.reverse()elementsinthereverselistKnowledgePoints知識點【列表方法】方法描述list.sort([func])對原列表進(jìn)行排序list.clear()清空列表list.copy()復(fù)制列表list.sort([func])對原列表進(jìn)行排序12345a=['Hello','Deris','Weng']

a.append('Happy')

print(a)

a.reverse()

print(a)【例】列表方法的使用['Hello','Deris','Weng','Happy']['Happy','Weng','Deris','Hello']輸出結(jié)果：MethodsDescriptionlist.sort([func])Sortingtheoriginallistlist.clear()Emptythelistlist.copy()Copythelistlist.sort([func])Sortingtheoriginallist12345a=['Hello','Deris','Weng']

a.append('Happy')

print(a)

a.reverse()

print(a)[Example]Theuseofthelistmethod['Hello','Deris','Weng','Happy']['Happy','Weng','Deris','Hello'][Listmethod]KnowledgePointsOutputresult：Python語言程序設(shè)計【元組基礎(chǔ)】PythonLanguageProgramming[TupleBasics]知識點【聲明元組】1234tup1=(50)

print(type(tup1))#不加逗號，類型為整型

tup1=(50,)

print(type(tup1))#加上逗號，類型為元組【例】只包含一個元素的元組<class'int'><class'tuple'>輸出結(jié)果：創(chuàng)建空元組tup1=()KnowledgePoints[declarationtuple]1234tup1=(50)

print(type(tup1))#Withoutcomma,thetypeisinteger

tup1=(50,)

print(type(tup1))#Addacomma,andthetypeistuple[Example]Atuplecontainingonlyoneelement<class'int'><class'tuple'>Creatinganemptytupletup1=()Outputresult：知識點【訪問元組】1234tup1=('Deris','Weng',1,2)

tup2=(1,2,3,4,5,6,7)

print("tup1[0]:",tup1[0])

print("tup2[1:5]:",tup2[1:5])【例】訪問元組tup1[0]:Deristup2[1:5]:(2,3,4,5)輸出結(jié)果：[Accesstuple]1234tup1=('Deris','Weng',1,2)

tup2=(1,2,3,4,5,6,7)

print("tup1[0]:",tup1[0])

print("tup2[1:5]:",tup2[1:5])[Example]Accessingthetupletup1[0]:Deristup2[1:5]:(2,3,4,5)KnowledgePointsOutputresult：知識點【修改元組】1234tup1=(12,34.56);

tup2=('abc','xyz')

tup3=tup1+tup2;

print(tup3)【例】修改元組(12,34.56,'abc','xyz')輸出結(jié)果：123tup1=(12,34.56)

#以下修改元組元素操作是非法的。

tup1[0]=100【例】非法訪問元組Traceback(mostrecentcalllast):File"tupError.py",line3,in<module>tup1[0]=100TypeError:'tuple'objectdoesnotsupportitemassignment輸出結(jié)果：元組自身不能修改[Modifytuple]1234tup1=(12,34.56);

tup2=('abc','xyz')

tup3=tup1+tup2;

print(tup3)[Example]Modifythetuple(12,34.56,'abc','xyz')123tup1=(12,34.56)

#Thefollowingtupleelementmodificationoperationsareillegal.

tup1[0]=100[Example]IllegalaccesstotupleTraceback(mostrecentcalllast):File"tupError.py",line3,in<module>tup1[0]=100TypeError:'tuple'objectdoesnotsupportitemassignmentThetupleitselfcannotbemodifiedKnowledgePointsOutputresult：Outputresult：知識點【刪除元組】12345tup=('Deris','Weng',1,2)

print(tup)

deltup;

print("刪除后的元組tup:")

print(tup)【例】元組中的元素不允許刪除，只可刪除整個元組Traceback(mostrecentcalllast):('Deris','Weng',1,2)File"C:/delTup.py",line5,in<module>print(tup)NameError:name'tup'isnotdefined刪除后的元組tup:輸出結(jié)果：[Deletetuple]12345tup=('Deris','Weng',1,2)

print(tup)

deltup;

print("Deletedtupletup:")

print(tup)[Example]Theelementsinthetuplearenotallowedtobedeleted,onlythewholetuplecanbedeletedTraceback(mostrecentcalllast):('Deris','Weng',1,2)File"C:/delTup.py",line5,in<module>print(tup)NameError:name'tup'isnotdefinedDeletedtupletup:KnowledgePointsOutputresult：元組的特點正好可以“彌補(bǔ)”Python沒有常量的“遺憾”，程序中不需要修改的數(shù)據(jù)都可以聲明在元組中。問題:為什么要設(shè)計元組？提問【元組基礎(chǔ)】Thecharacteristicsoftuplescanjust"makeup"the"regret"thatPythondoesnothaveconstants.Datathatdoesnotneedtobemodifiedintheprogramcanbedeclaredintuples.Question:Whydesigntuples?Askaquestion[TupleBasics]Python語言程序設(shè)計【元組運算符+索引與截取+內(nèi)置函數(shù)與方法】PythonLanguageProgramming[TupleOperators+IndexingandIntercepting+Built-inFunctionsandMethods]

+

和

*

的操作符+號用于組合，*號用于重復(fù)知識點【元組運算符】12345print(len((1,2,3)))#計算元組元素個數(shù)

print((1,2,3,4)+(5,6))#元組的拼接

print(5in(1,2,3,4,5,6))#元素是否存在于元組中

forxin(1,2,3):#元組的迭代

print(x,end="")【例】元組運算符3(1,2,3,4,5,6)True123輸出結(jié)果：

+and*operatorsThe+signisforcombinations,the*signisforrepetitionsKnowledgePoints[Tupleoperator]12345print(len((1,2,3)))#Calculatethenumberoftupleelements

Print((1,2,3,4)+(5,6))#Splicingoftuples

print(5in(1,2,3,4,5,6))#Whethertheelementexistsinthetuple

forxin(1,2,3):#Iterationoftuples

print(x,end="")[Example]Thetupleoperator3(1,2,3,4,5,6)True123Outputresult：知識點【元組運算符】12print(('Happy！',)*3)#有逗號(,)的情況下實現(xiàn)元組的重復(fù)倍增

print(('Happy！')*3)#沒有逗號(,)，不認(rèn)為是元組?！纠吭M的使用('Happy！','Happy！','Happy！')Happy！Happy！Happy！輸出結(jié)果：12print(('Happy！',)*3)#Repeatmultiplicationoftupleswithcommas(,)

print(('Happy！')*3)#Thereisnocomma(,)anditisnotconsideredasatuple.[Example]Theuseoftuples('Happy！','Happy！','Happy！')Happy！Happy！Happy！KnowledgePoints[Tupleoperator]Outputresult：知識點【元組索引與截取】1234Tup=('Deris','Happy','Weng')

print(Tup[2])#讀取第三個元素

print(Tup[-2])#反向讀取；讀取倒數(shù)第二個元素

print(Tup[1:])#截取元素，從第二個開始后的所有元素【例】索引與截取WengHappy('Happy','Weng')輸出結(jié)果：KnowledgePoints[TupleIndexingandInterception]1234Tup=('Deris','Happy','Weng')

print(Tup[2])#Readthethirdelement

print(Tup[-2])#Reversereading;Readthepenultimateelement

print(Tup[1:])#Interceptelements,allelementsafterthesecondone[Example]IndexingandInterceptionWengHappy('Happy','Weng')Outputresult：課后練習(xí)【元組截取與拼接】問題:

tup1=（1,2,3,4,5,6,7）print("tup1[0]:",tup1[0])print("tup1[1:5]:",tup1[1:5])結(jié)果分別是什么？After-schoolexercises[Tupleinterceptionandsplicing]Question:tup1=（1,2,3,4,5,6,7）print("tup1[0]:",tup1[0])print("tup1[1:5]:",tup1[1:5])Whatweretheresultsrespectively?課后練習(xí)【元組截取與拼接】Python表達(dá)式結(jié)果描述len((1,2,3))長度(1,2,3)+(4,5,6)組合('Hi!',)*4重復(fù)3in(1,2,3)元素是否存在于列表中3(1,2,3,4,5,6)('Hi!','Hi